1. Field of the Invention
The invention relates to a vehicle including at least an electric motor capable of delivering power to a drive shaft coupled to driving wheels and electric storage means capable of supplying and receiving electric power to and from the electric motor, and a method of controlling the vehicle.
2. Description of the Related Art
A hybrid vehicle is known which includes an engine, a planetary gear mechanism having a planetary carrier connected to a crankshaft of the engine and a ring gear connected to a drive shaft coupled to driving wheels, a first motor connected to a sun gear of the planetary gear mechanism, and a second motor connected to the drive shaft, and which permits the driver to select one of a plurality of virtual shift positions (see Japanese Patent Application Publication No. 2008-201261 (JP-A-2008-201261), for example). In the hybrid vehicle of this type, when one of the virtual shift positions is selected by the driver, the lower limit of the engine speed is set based on the selected virtual shift position and the vehicle speed, and the engine is operated at a rotational speed equal to or higher than the lower limit of the engine speed. In this manner, when one of the virtual shift positions is selected by the driver and the accelerator pedal is depressed, the engine speed can be kept high to some extent, thus assuring the output response of the engine.
However, the output response or responsiveness of the driving force for running the vehicle to a shifting operation performed by the driver is not always satisfactory if only the lower limit of the engine speed is set based on the virtual shift position and the vehicle speed as in the hybrid vehicle as described above. For example, some drivers may feel unsatisfied with the acceleration feeling of the vehicle responsive to a shifting operation. On the other hand, other drivers may wish to improve the energy efficiency (fuel efficiency) through shifting operations, in the hybrid vehicle as described above, an electric vehicle, or the like.